Machine for grinding and polishing lenses



No. 6l9,793. Patented Feb. 2|, I899 E. SCHADELI.

MACHINE FOR GRINDING AND POLISHING LENSES.

(Application filed Sept. 25, 1897.)

3 Sheets-Sheet I.

(No Model.)

Inventor.- 671! 0.. FHOTO-LITHO., wuumcrmm D. c.

No. 6I9,79'3. Patented Feb. 2I, I899. E. SGI'IADELI.

MACHINE FOR GRINDING AND POLISHING LENSES.

. (Application filed Sept. 25, 1897.) (No Model.) 3 Sheets-Shoat 2.

five-n for:

W7 ma No. (muss. Patented I-eb; 2|, I899.

- E. SCHADELI.

MACHINE FOB GRINDING AND POLISHING LENSES.

(Application filed Sept. 25, 1897.)

(No Mqdal.)

3 Sheets$heet 3.

UNITED, STATES I PATENT OFFICE.

EMIL SCHADELI, OF ROCHESTER, NEW YORK.

MACHINE FOR GRINDING AND POLISHING LENSE S.

SPECIFICATION forming part of Letters Patent N 0. 619,793, dated February 21, 1899. Application filed September 25, 1897. Serial No. 658,001- (No model.)

To all whom, it nzay concern.-

Be it known that I, EMIL SoHADELI, of Rochester, in the county of Monroe and State of New York, have invented a new and useful Improvement in Machines for Grinding and Polishing Lenses, which improvement is fully set forth in the following specification and shown in the accompanying drawings.

The human eye frequently is at first or subsequently becomes organically defective in structure, rendering vision imperfect, astigmatism being among the most common of these structural difficulties. To compensate for or neutralize the effects of these imperfections of the eyes, glass lenses of various forms and curvatures are constructed to be used with the eyes, the nature of the curvature of the lenses used in any given case depending upon the kind and degree of the optical defects.

The machine herein shown and described is designed more particularly for the purpose of producing astigm atic lenses as near mathematically perfect as possible, two lenses being formed at once. The part holding the lenses is given motions upon two axes 0ccu-' pying planes at right angles with each other, the axes being at different distances from the lenses. These centers of motion are relatively adjustable, and the motions from the axis nearest the lenses give a shorter or stronger curve to the lenses than those from the more distant axis. Means are also provided for properly moving the lenses over the grinding-surface, said means comprising various adjustments necessary for producing the desired results.

The invention is hereinafter fully described, and more particularly pointed out in the claims.

Referring to the drawings, Figure l is a front elevation of the machine, parts being shown in various positions by full and dotted lines and the driving parts omitted. Fig. 2 is a side elevation seen as indicated by arrow in Fig. 1, parts being shown in various positions by full and dotted lines, with driving parts omitted. Fig. 3 is a plan view indicated by arrow 3 in Fig. 2, parts being broken away. Fig. 4 is a vertical section of the lenscarrier and some associated parts, taken on the dotted line4 4in Fig. 2, parts being broken away. Fig. 5 is aside elevation of parts of the device seen as indicated by arrow 5 in Fig. 4. Fig. 6 is a vertical section of the sliding head, showing the contiguous part of the holder therefor. Fig. 7 is a plan of the driving mechanism, the lens-carrier being horizontally sectioned, as on the dotted lines 7 7 in Figs. 2 and 4, parts being broken away. Fig. 8 is a front elevation of the driving mechanism, parts being broken away. Fig. 9 is a cross-section of the lower part of the lens-carrier and the lens-holder, taken on the dotted line 9 in Fig. 7. Fig. 10 is a vertical section of the lens-holder and a part of the grinding-shell, showing the curvature of the latter. Fig. 11 shows the adj ustability of the operating-eccentric. Fig. 12 shows the adj ustability of the rocking crank. Fig. 13 is a perspective view showing one of the devices in operative position. Figs. 4, 5, 9, and 10 are drawn to scales larger than that of the other figures.

Referring to the drawings, A, Figs. 1, 2, and 3, is a vertical standard having a horizontal foot piece or ledge B (see also Figs. 4 and 5) extending at one side thereof.

0 is a bracket adapted to slide vertically along the standard, being held rigidlyin place in its different positions by a clamping-bolt a. This bolt passes through a vertical slot b in the standard and is threaded in the body of the bracket. The bracket supports a swinging carrier D by means of an axial-pin 0, held rigidly in the bracket by a set-screw d. This axial pin is horizontal, and the swinging carrier turns freely thereon. This swinging carrier holds a vertical sliding head E, which is formed with an undercut groove e, fitting the T-shaped end f of the carrier, the sliding head being adapted to move vertically along the carrier. Theslidin g head E carries at its lower end a lens-carrier F by means of an axial bolt g (Fully shown in Fig. 4.) The head is formed with an enlarged horizontal part h, centrally within which is placed a sleeve or bushing 2', through the center of which the axial bolt g passes. The lens-carrier F is U-shaped, the branches of which pass over the lower end of the sliding head and the sleeve '5. The lenscarrier is provided at either side with vertical slots 70, through which the axial bolt g passes, allowing said carrier to be moved vertically upon its bearings upon the sliding head. The bolt 9 is formed at one end witha rigid head Z, lapping across the adjacent slot 7t, and at the other end is provided with a threaded thumbnut 011, working against a washer a, crossing the ad jaoent slot 7;. The sleeve 71 is slightly longer than the width of the sliding head, so that it bears at its ends directly against the inner vertical faces of the lens-carrier, said faces being slightly separated from the oppos in g faces of the sliding head to form free joints between them. \Vhen, therefore, the axial bolt gis tightened up, the branches of the lenscarrier are firmly pressed against the ends of the sleeve, the lenscarrier being permitted to swing freely upon the sliding head on account of the sleeve turning therein.

At the lowerend of the lens-carrier is placed an angle-block or lens-holder 0, Figs. 4, 5, and 10, against the lower faces of which the lenses 1) p are secured by cement or other adhesive substance for the purpose of grinding. The upper surface of the lens-holder is plain and meets the lower plane surface of the lens-carrier, the holder being provided with vertical pins 0" 0', passing upward through the lens-carrier and holding to place by friction. The lower surface of the angle-block orlens-holder is formed of two inclined plane surfaces intersectin g in a horizontal line at the middle, said line being transverse to the plane of the lenscarrier.

Beneath the lenses and secured to the foot 13 of the standardis a grinding-shell G, against which to grind the surfaces of the lenses. This grinding-shell is formed with a part 8 projecting downward through the foot B, a clamping-screw t and washer to being provided to hold the shell firmly to place upon the foot.

Now by referring to Fig. 1 it will be understood that the lateral motions of the lower faces of the lenses will be in arcs of a circle having a radius reaching from the axis 0 to said faces, while the forward and backward motions of said faces (indicated by dotted lines in- Fig. 2) will be along arcs of a circle having a radius reaching from the axis 9 to said faces, and, furthermore, that if these radii are unequal the curvature given the lenses will be of a compound nature, the flatter curvature being produced by the motions upon the axis 0 and the sharper curvature produced by the cross-motions upon the axis g. The fiat curvature is shown in Fig. from e to "0, while the sharp curvature is shown in Fig. 10 from w to w.

The grinding-shell is preferably made of iron and concaved, upon which concaved surface are placed the grinding or polishing materials commonly used for such work. The form, however, of the grinding-surface of the shell is not essential, for by the means employed for determining the motions of the lenses they would be accurately ground were the surface of the shell in a plane. Prefer-- ably the shell is made concave on its upper surface, for in this form it better holds the grinding and polishing materials and serves to grind the lenses more rapidly, for in this case all of the lowersurfaces of both lenses are being acted upon simultaneously. I usually form the concave face of the wooden pattern for the shell by means of the machine itself. To effect this, a cutting-tool is placed in the lens-holder with its downwardly-projeeting end in position to act upon and form the surface of the pattern when the machine is operated.

To give the parts proper motion for grinding the lenses, mechanism shown mainly in Figs. 7 to 9, inclusive, is employed. In this mechanism 11 is a shaft resting in suitable bearings I I and given a rectilinear reciprocating motion by means of an eccentric L and intermediate parts. Rigid with the shaft is a pair of links N N, carrying at their upper ends another shaft 0, parallel with the shaft H. The shaft 0 is rigid with the links and partakes of the reciprocatory motions of the links and the shaft H. The shaft 0 holds a forked manipulator P, connected with the lens-carrier by means of an axial rod R. This rod is longitudinally adjustable in the manipulator and held to place therein by a setscrew 00. S is a rocking arm connecting the shafts H and O and adapted to turn freely on both. This arm is provided with a lateral projection y at its lower end, connected with which is a pitman T, joined toa crankz of a horizontal shaft V, resting in bearings E. The eccentric L is held upon a horizontal shaft X, resting in bearings Y Y, the shaft being provided with a pulley Z, turned by a driving-belt A. The shaft is also provided with another pulley 13, carrying a belt 0, passing over a pulley D on the shaft V, by means of which the main driving-belt A operates the whole device. From the description given of this driving mechanism it will be understood that if the shafts X and V are both rotated the lens-carrier will be simultaneously swung both forward and backward and to the right and the left, giving the lenses circuitous or roundabout grinding motions upon the shell, at times roughly approaching in form circles or ellipses. Left to itself the eccentric would swing the lenscarrier laterally, asindicated by dotted positions in Fig. 1, while if not interfered with the crank z,with its connections,would swing the lens-carrier forward and backward, as indicated by dotted lines in Fig. 2, these two directions of motions crossing each other at right angles; butas both the eccentric and the crank operate simultaneously the swinging motions of the lens-carrier are neither wholly lateral nor forward and backward, but are made along compromise or resultant curved lines determined by the interfering cross motions or-thrustsof the eccentric and the crank. It will be further understood that if the shafts X and V revolve at difierent rates the motions of the lenses upon the grinding-shell will be neither repetitious nor reciprocal, but will be made along curved lines constantly changing and crossing each other through a long series, no two adjacent lines being parallel or alike. If the motions of the lenses upon the shell were circular or of other regular form and repeated, there would be a.

tendency to scratch or furrow the faces of the lenses, a thing studiously avoided in the matter of forming them. To avoid a possibility of such repetition of the motions of the lenses, the shafts X and V are given different rates of motion, this being effected by making the pulleys B and D of different diameters, the latter,for example, being the smaller. As aresult of this, the forward and backward motions and the lateral motions of the lenscarrier will be unequal as to period, one motion gaining upon the other as both progress, and this inequality of the periods of the cross-thrusts of the eccentric and the crank also causes the directions of the circuitous motions of the lens-carrier to be periodically reversed-that is to say, if said carrier be moving in circuits, say, from right to left these circuits will gradually narrow until they approximate a straight line, when the directions of the circuit motions will be reversed or be made from left to right, and the figures, now formed on the other side of the dividingline, will widen until a circle or broad ellipse is approximated. Culminating, the circuit figures will commence to narrow, as before, until the direction of motion is again reversed at the dividing-line, and this process of passing through cycles will be repeated as long as the machine is kept running. This changing circuit motion of thelenses amounts to a scouring motion, which is the kind desired for the purpose of grinding, and the mechanism that produces this motion is an essen tial part of my invention.

Provision is also made for changing the lengths of the throws of the eccentric andthe crank for the purpose of controlling the forward and backward and the lateral distances through which the lens-carrier is moved. By these means the forms of the circuits traversed by the lenses upon the grinding-surface, or, in other words, the motions of the lenses, may be changed at pleasure. As shown in Fig. 11, the eccentric is laterally shiftable upon the shaft X. It is formed with an oblong opening a and with parallel slots 6 b, occupied by clamping-bolts c 0'. These bolts are rigid in a flanged hub d, secured rigidly to the shaft. By loosening the clamping-nuts e e the eccentric may be shifted at pleasure to regulate the amount of its eccentricity, this construction being common in machinery. I also prefer to insert the crank-pin z in a block f, Fig. 12, adapted to slide in a grooved head 9 transversely of the axis of .in the carrier F.

the shaft V. The head 9 is rigid with the shaft, and it, with the block and pin, is of common construction in machinery. By sliding the block toward or from the axis of the shaft the throw of the crank may be varied.

The pitman T is connected with the rockerarm S by some simple universal jointas, for instance, a ball and socketand also the eccentric is connected with the shaft H by some similar joint, such being common in machinery. The joint between the pitman and the crank z is also given some simple form to admit of a slight rocking of the pitman upon its bearing on the pin. It is not necessary that the eccentric L be employed to reciprocate the shaft H, as the common device shown in Fig. 12 might readily be substituted.

The rod R, Figs. 3, 4, 7, and 9, connecting the manipulator P and the lens-carrier F, is reduced near its outer end, bent downward, and formed with a terminal ball h, seated in a corresponding cavity in the lower part of the lens-carrier. This constitutes a kind of a universal joint between the carrier and the rod R, which is necessary on account of the various motions of the parts. A simple capplate '5, secured to the part F over the ball h, serves to prevent the latter leaving its seat The axes c and g are both horizontal, but not in a straight line, they occupying intersecting planes at right angles with each other. The parts are also vertically shiftable, so as to change the relation .of the two curves generated by swinging the parts upon the different axes. In setting the parts of the machine in any given case the clamping-bolt Ct is loosened and the bracket 0 moved upward or downward along the standard A to givethe required vertical distance between the axis 0 and the grindingsurface of the shell G. Likewise, the thumbnutm is loosened and the lens-carrier F moved upward or downward to give the required .vertical distance between the axis 9 and the grinding-surface of the shell.

By varying these two radii of the two arcs of motion differently-curved lenses may be produced.

The lenses formed as hereinbefore described are compound convex, the axes of the two curvatures being in planes at right an block 0. This grinding-body is readily formed by making a plaster-of-paris cast in the concavity of the shell G and securing the same to the carrier F.

The sliding head E is adapted to move freely in vertical directions along its bearing upon the swinging carrier D. lts weight, together with that of the dependent parts and the manipulator P, serves to press the lenses ICC against the shell G for the purpose of grinding.

In practice several of these grinding devices are placed side by side upon a bench, the shafts H and 0 being made suliiciently long to act for all.

\Vhat I claim as my invention is- 1. In a machine for grinding lenses a carrier or holder for the lens, and means for giving it motions producing curves of different lengths from or upon two independent centers, substantially as shown and described.

2. In a machine for grinding lenses a carrier or holder for the lens, and means for giving it motions producing greater and less curvatures from or upon two independent centers, said centers being at different distances from the lenses, substantially as specified.

3. A machine for grinding lenses, having a carrier or holder for the lenses, and means for giving it motions from or upon two independentaXes,said axes being out of astraight line, substantially as shown and described.

4. A machine for grinding lenses, having a carrier or holder for the lenses, and means for giving it motions from or upon two independent axes, said axes beingout of astraight line and lying in intersecting planes, as specified.

5. In a machine such as described, acarrier or holder for the lenses, and means for giving it motions from or upon two independent centers or axes, said centers or axes being shiftable or relatively adjustable, substantially as shown and described.

6. A machine such as described, having a carrier or holder for the lenses, and means for giving it motions from or upon independent centers to give curves of different degrees, in combination with a body or part having a grinding-surface for the lenses, substantially as shown and described.

7. A machine for grinding lenses, having a lens-carrier and means for giving it motions from or upon two independent centers, and a holder for the lenses, controlled by said carrier, said holder being formed with two inclined intersecting faces, substantially as shown and described.

8. In a machine for grinding lenses a carrier or holder for the lenses and means for giving said carrier or holder different circuitous motions from or upon two independent centers, as set forth.

9. A machine for grinding lenses, having a carrier or holder for the lenses, and means for moving said carrier or holder circuitously to give curves of different degrees of sharpness, the directions of the circuitous motions periodically changing, substantially as described.

10. In a machine for grinding lenses a carrier or holder for the lenses mounted for pcriodically changing circuitous motions and means out of a straight line for moving said carrier or holder in resultant lines of crossthrusts, substantially as described.

11. In a machine for grinding lenses a carrier or holder for the lenses, adapted to have motions from or upon two independent centers and means for adjusting said centers, in combination with means for moving said carrier or holder in resultant lines of crossthrusts, substantially as specified.

12. A machine of the kind described, having a carrier or holder for the lenses, in combination with operating mechanism adapted to move said carrier or holder in lines at right angles with each other, substantially as and for the purpose specified.

13. A machine such as described, havinga carrier or holder for the lenses, in combination with operating mechanism adapted to move said carrier or holder in lines or directions crossing each other, the motions in said different directions being unequal as to time, substantially as shown and described.

14. In a machine for grinding lenses a carrier or holder for the lenses, in combination with operating mechanism adapted to move said carrier or holder in lines or directions crossing each other, with adjustments for changing the distances through which said motions are made, substantially as shown and described.

In witness whereof I have hereunto set my hand, this 23d day of September, 1897, in the presence of two subscribing witnesses.

EMIL SOIIADELI.

Witnesses:

ENos B. WHITMORE, M. L. WINSTON. 

